This invention relates to an apparatus and method for resealing a sterilized container, and more particularly, to a sterile seal for resealing the container after the original seal is broken and for providing an indication on the rim of the container top that the seal has been removed.
In many hospitals, intravenous (I.V.) additive programs are administered as a way of introducing medication into a patient. Typically, a drug which is prescribed by a doctor, is added to an intravenous solution. The medication is added into an I.V. bottle under sterilized conditions by inserting a needle into a target area rubber membrane which closes the top of the I.V. solution bottle or container.
Such bottles or containers typically have a sterile seal covering a membrane area, typically a rubber membrane, until the medication is to be added. The medication is added after removal of the seal, and penetration of the membrane with a medication administering needle. The container must then be resealed under sterilized conditions to prevent airborne bacteria from accumulating on the exposed upper surface of the I.V. container top. By resealing the container, the hospital staff is also alerted that the contents have been altered. In operation, the staff will not administer the I.V. solution unless they mix the contents themselves, or there is some means to alert the staff that the contents have not been altered since its preparation with the added medication.
In the past, plastic caps have been utilized for resealing such I.V. containers. Such caps typically snap over the top of the metal rims surrounding the rubber membrane to completely seal the top of the solution bottle. The problem with this approach has been that since the I.V. solution and containers manufactured by different manufacturers have tops which are not of uniform diameter, the plastic caps do not always provide the necessary sterilized seal in resealing the I.V. container.
One prior art approach to solving the problems inherent in the use of plastic caps has involved forming a seal out of a combination of materials and bonding systems. Typically, such seals involve an impermeable upper layer such as polypropylene, and a non-adhesive surface to cover the rubber membrane target area of the container top. A self-destructing adhesive layer has been included in the laminated structure and arranged to form an annular ring surrounding the circular target area to have the adhesive material adhere tightly to the metal ring surrounding the rubber membrane target area. Any removal of the seal then left a telltale strip of material affixed to the metallic rim from the self-destructing adhesive, which indicated to hospital staff that the seal has been previously broken. The presence of the telltale material on the rim of the cap was intended to reduce the chance of someone removing the seal, allowing the top to become contaminated and resealing the container with that seal or a new seal so that it would appear to staff to be in sterilized condition.
A disadvantage with type of system is, however, that the adhesive layer due to its self destructing nature, leaves a messy residue on the rim and potentially on the rubber membrane. A further disadvantage is that a leaving a residue of adhesive material, although allegedly self-destructing, may still retain some adhesive quality allowing resealing of the container either with the old seal or with a new seal, and thus allowing circumvention of its indicating feature. In fact, due to the nature of this design, incomplete delamination may often occur, leaving the target membrane partially blocked.
An alternative approach to this type of seal has involved providing a similar sealing cover which includes slits formed in the cover to promote its tearing to leave telltale sealing strips on the container upon removal of the cover. The problem with this type of arrangement, however, is that it relies on tearing of the cover in a very precise manner, which in turn requires very expensive process control conditions in the manufacturing of the seals to ensure that proper tearing occurs so that the seal can be used in the manner intended. Further, by leaving telltale strips, resealing with a second seal may result in an imperfect seal, resulting in bacterial contamination.
In accordance with this invention, the problems of the prior art plastic caps and the multiple layer seals are avoided, while providing an easily used seal which provides a clear indication upon removal to prevent its reuse to reseal the container with which it is employed.
In accordance with one aspect of the invention, there is provided a sealing cover for resealing a membrane of a container in a sterile manner. The sealing cover includes an upper, substantially impermeable to moisture and bacteria, cover member. A first adhesive layer is arranged in a ring shape on the bottom of the cover member for adhering the cover member to an annular ring member made of substantially impermeable moisture and bacteria material. A second adhesive layer is disposed on the bottom of the annular ring member for adhering the annular ring member to the rim of the container for sealing the membrane of the container in a sterile manner.
The first adhesive layer is such that, upon separation of the upper cover member from the annular ring member, substantially no visible indication of adhesive residue is left on the annular ring member, or on the upper cover member. The first adhesive layer also loses its adhesive properties upon the separation of the upper cover member. The second adhesive layer is such that when the upper cover member is separated from the annular ring member, the annular ring member is held securely on the rim of any container to which the annular ring member has been attached.
In this manner, contrary to the prior art, the seal is effectively destroyed by leaving half the seal, i.e., the annular ring member is held securely on the rim of any container with which it is used. Thus, this serves as a visual indicator to anyone attempting to reseal the container with a new seal, or with the other seal, since the first adhesive is such that when separated, loses all of its adhesive properties, and at the same time, the annular ring member retained on the rim serves to indicate that resealing should not be attempted.
In a more preferred aspect, a pull tab is connected to and extends from the upper cover member. The upper cover member is preferably made of metalized Mylar, a registered trademark for a polyester film materal, a polyester based material commercially available from Dupont Corporation, and the annular ring member is preferably made of clear Mylar. Although Mylar material has been indicated as preferred, other polyester based alternatives available commercially can be substituted in place thereof. The first adhesive layer is typically UV cured varnish, with the second adhesive layer being a pressure sensitive adhesive, i.e., an adhesive that is not easily removed.
In another aspect, the invention is directed to a strip of carrier liner having a plurality of sealing covers removably carried thereon. The liner is a base liner layer, and includes a plurality of sealing covers of the type previously described. The base liner is made of a material which allows removal of each sealing cover intact with the second adhesive layer thereon without substantially effecting the adhesive properties of the second adhesive layer.
In yet still another aspect, there is provided a method of resealing the top of a solution bottle having a rim and a pierceable membrane covering the opening of the bottle inside the rim. The method involves forming an upper, substantially impermeable to moisture and bacteria, cover member. A first adhesive layer is disposed in a ring shape on the bottom of the upper cover member and an annular ring member, made of substantially impermeable to moisture and bacteria material, is joined to the upper cover member through the first adhesive layer. The first adhesive layer is such that the upper cover member can later be separated from the annular ring member, leaving substantially no visible indication of adhesive residue on the annular ring member. A second layer of adhesive is disposed on the bottom of the annular ring member for adhering the annular ring member to the rim of the container. The second layer of adhesive is such that when the annular ring is attached to the rim, and the upper cover member is attached to the annular ring, the upper cover member can be detached therefrom without detaching the annular ring member from the rim. The upper cover member, first adhesive layer, annular ring member and second adhesive layer are joined to form an integral laminated cover for use as a sealing cover. The cover is then attached to a strip of carrier liner, sterilized and packaged to maintain sterility prior to use, and thereafter the cover is removed from the liner and applied to the top of the bottle with the second adhesive layer in contact with the rim at the opening of the bottle.